Invasive Pest Alert: Asian Jumping Worms Confirmed in Colorado, Preventing Spread is Key

Gardening season is arriving much earlier than usual this year, and the Colorado Department of Agriculture (CDA) wants to alert residents about a new aggressive, invasive species found in Colorado. Last October, CDA confirmed the presence of the Asian jumping worm in the Hilltop neighborhood of Denver. The worms are an annual species, but their cocoons (about the size of a mustard seed) survive the winter and are easily spread in soil, mulch, and on equipment. CDA is encouraging vigilance to prevent the spread of this invasive pest.

Since there are currently no effective eradication methods for this pest, CDA is launching a public education campaign to emphasize prevention and prompt reporting to slow the spread of this pest. CDA is asking nurseries, landscaping contractors and landowners to be on the lookout for any signs of the invasive jumping worms and report any suspected sightings .

"Preventing any spread of the jumping worm in Colorado is critical to protecting our state's healthy soil and native plants," said Wondirad Gebru, Director of the Plants Division at CDA. "Since there are no effective eradication methods, we are asking gardeners and landscapers to be vigilant, inspect their materials, and report any possible sightings to our agency."

While many earthworms are beneficial to the soil, adding nutrients for plants and helping with soil aeration, the jumping worm poses a significant ecological and economic threat. It lives on the soil surface, rapidly consuming organic matter and leaf litter, which strips the soil of the critical layer needed to support native plants, wildflowers, and forest ecosystems.

The jumping worms' hyper-activity degrades the soil structure, can harm plant roots and accelerate soil drying. This creates a "nutrient-poor paradox" where nutrients are present but unavailable to plants. This can further exacerbate drought conditions, which the state is already in.

Prevention

There are no effective eradication methods for the jumping worm. CDA urges all residents and industry professionals to adopt the following best practices for prevention:

• Do Not Move Soil: Avoid moving soil, compost, or potted plants from your yard if you suspect an infestation.
• Inspect Materials: Always carefully inspect all potted plants and soil before moving, sharing, or bringing them into your garden. Consider purchasing bare-root stock when possible.
• Check Compost Sources: When purchasing bulk mulch or compost, ensure it has been heat-treated to at least 130°F for three days by a reputable producer to kill the cocoons.

Reporting

The public's help is critical to track the spread of the pest. If you suspect an infestation, please report it to CDA using the Jumping Worm Reporting Form . For more information, please visit CDA's jumping worm website .

What is the Asian Jumping Worm?

The Asian Jumping Worm, also known as the "crazy worm" or "snake worm," is an invasive earthworm species ( Amynthas spp . and Metaphire spp .) that is rapidly spreading across the United States.

• Identification: They are long, red-to-brown colored worms that thrash and move erratically with a violent, snake-like motion when disturbed. A key difference from native earthworms is the clitellum (the band around the body): on the AJW, it is milky white to light gray, flush with the body, and completely encircles it.
• Signs of Infestation: The most telltale sign is a very uniform, granular soil texture on the surface, often described as looking like "coffee grounds," which are their castings (feces).

You can download an informational poster about the jumping worm to professionally print or share digitally .

Protecting Colorado's Plants

Protecting Colorado's environment, from agricultural crops to forests, is a shared responsibility. Through the Pest Survey program , CDA works with growers and forest managers to mitigate the risk of invasive species in our state. Part of our risk mitigation strategy involves communicating invasive pest detections to the public. Early detection is key to stopping invasive species in their tracks before they form established populations. By working together as a community, we can ensure the security of Colorado's good supply and natural systems.